Trust No One
by acertainzest
Summary: In episode 3x09, "Close Encounters Of The Murderous Kind," Beckett and Castle wake up with mysterious marks on their necks. They aren't hickeys. Or are they?
_Castle: "I'm not asking you to dye your hair red and call me Mulder..."_
 _Beckett: "Castle, the truth - the real truth - is out there."_  
 _-episode 3x09, Close Encounters of the Murderous Kind_

* * *

Stepping out of Captain Montgomery's office, Castle was feeling a little disappointed. He supposed that "detained for questioning by shadowy government operatives" was pretty good, as far as interesting experiences while collaborating with the NYPD, but it was no "abducted by aliens." Oh well, maybe next week.

"Abducted by government agents, huh?" Esposito deadpanned as Castle and Beckett took their customary seats at Beckett's desk. "Come on, what were you two really doing?"

Castle bristled, but Beckett was faster. "It's not a hickey, Esposito."

Castle's eyes were drawn once again to the dark circle marring her neck. He had to admit, it really did look like a hickey. His fingers lifted to his own neck, tracing the contours of the mark on his skin.

"You both have one," Espo pointed out, smirking.

"I wish it was a hickey," Castle declared, and saw Beckett's eyes widen. Oh. Oops. He hadn't meant it that way ... well, maybe just a little ... _Stay focused, Rick_. "It's from the injectors," he declared firmly, but for some reason Esposito didn't seem convinced.

Beckett quirked an imperious eyebrow and got Espo back on track, updating them on his attempts to track down evidence for the case. A moment later, Ryan joined them.

"Hey," he said. "Those hickeys?"

"Yes," said Esposito.

"I wish," said Castle, because what the hell, in for a penny, in for a pound.

"N-" Beckett began, but then she paused and frowned slightly, cocking her head. "Wait a minute."

"What?" Castle felt his eyebrows heading toward his hairline. He watched in fascination as a slow blush crept across Beckett's face, tinting her cheeks a really very attractive shade of pink. "Beckett?"

Abruptly she shot up out of her seat and made a beeline for the ladies' restroom, leaving the three men to stare at each other in bemusement.

"What the hell just happened?" Espo asked, narrowing his eyes at Castle, who put up both hands in self-defense.

"How should I know?" He instinctively recoiled from the scrutinizing glares of both detectives, pressing his back against the chair. Esposito and Ryan folded their arms across their chests and pinned him with their jaded gazes. He gulped.

* * *

Beckett locked herself into a stall in the restroom and let out a long, shaky breath. But her eyes were dry and her lips curved upward; the tremble in her exhale was not from impending tears but from the strain of holding back laughter.

She wasn't sure where the impulse had come from, but something in the earnest way Castle had said _I wish it was a hickey_ had put a wicked, evil idea into her head. She snickered quietly to herself in the privacy of the restroom, thinking about it.

The only real question was whether she'd be able to pull this off without bursting into laughter halfway through.

She took another deep breath and composed herself. Emerging from the stall, she checked herself quickly in the mirror and then went back out to the bullpen.

Not terribly to her surprise, she found the three men glaring at each other. The box of electronic components sitting on her desk between them was more unexpected.

"What's this?"

"Hmm? Oh," said Ryan, breaking free from the staring contest. "These are the tracking devices that CSU found on your car."

"And I was-" began Castle, but Esposito overrode him.

"And *I* was just telling Castle that the object in Marie's nose was a calcification resulting from a sinus infection. Not metal, just looks like it on the x-ray."

"There you go, a logical explanation," Beckett said, pleased.

Castle wasn't fazed. "I would disguise my tracking implant as a rare medical phenomenon too," he insisted, "just like I would disguise my sedative injection site as a hickey."

Aha! That was Beckett's cue. She called upon her years of experience in the interrogation room to keep her expression perfectly blank.

"Castle, it's okay. You don't have to lie to the boys. They need to know the truth if we're going to crack this case."

Castle blinked at her, completely flummoxed. "What - what truth?"

She cocked her head and allowed a small perplexed frown to crease her forehead. "About the hickey."

The slow spread of amazement across Castle's face was a thing of beauty. Beckett thought she would probably be cherishing that memory for years to come. She could practically read his thoughts on his face: something very much like _holy shit she called it a hickey, wait what?!_ She had to work very hard to maintain her neutral expression.

"I - wha - you - what?" he babbled, thoroughly disconcerted. The boys were staring from one of them to the other and back, caught somewhere between amusement, confusion, and suspicion.

"I figure they must have used some form of highly classified memory-erasing technology," Beckett continued calmly, "but they were in a rush and didn't calibrate the sensors properly, hence why we retained some of the memory of the interrogation and," she paused significantly, cleared her throat, lowered her eyes toward the floor to give the appearance of embarrassment, "the aftermath."

"Aftermath?" Esposito repeated, his look of suspicion beginning to tilt back toward the smirk end of the spectrum.

"What aftermath?" Castle squeaked, his eyes bigger than Beckett had ever seen them. She gave him her surprised look again.

"You mean ... you don't remember?"

"Remember what?" His renowned vocabulary seemed to be on the fritz. It was delightful.

Beckett paused again, frowning. She was debating how long to drag out the suspense, but Castle broke much more quickly than she expected.

"Beckett!" he pleaded, his hand lifting almost of its own volition, as if it wanted to grab her shoulder and shake the answers out of her. "What am I not remembering?"

"I ... Maybe I shouldn't tell you," she said, putting a hesitant hitch into the sentence. "I mean, we don't know exactly what they did to us, and sometimes re-inserting erased memories can cause severe brain trauma."

It was complete bullshit, but she thought it probably sounded convincing. At least, she thought Castle would buy it, in the credulous state in which he seemed to have spent this entire case so far. She forced herself not to roll her eyes at the thought.

Castle had turned to Espo and Ryan for confirmation. "Really? Is that true?" he asked in their direction, but they both shrugged.

"Beats me," said Espo. "I don't know nothin' about that spooky shit."

"I've never heard of a technology that could cause selective memory loss like that," Ryan picked up, frowning thoughtfully, "but it's possible, I guess." He was eyeing Beckett curiously, and she could see questions brimming in his gaze, so she quickly redirected them all back to the murder board.

Within moments they had decided to contact the victim's ex-boyfriend and ask him about the items that Marie had given him just before her death. But it was too late for that now; they would ask him to come to the precinct first thing in the morning.

Beckett made the call, and she could feel Castle's eyes on her the whole time. As soon as she hung up, he started in on her again.

"Come on, Beckett. You gotta tell me about the memories that they erased."

"Castle, I just don't think it's a good idea." She opened her desk drawer and took out her purse. "We should both get a good night's sleep. Maybe the rest of the memories will come back on their own overnight."

"The rest?" Just as she had hoped, he was distracted by the implication. "You mean you think there might be more memories that you haven't recovered either?"

"Well, you never know, Castle. After all, we aren't entirely sure how much time we lost." She grabbed her jacket and headed for the elevator. Castle, of course, followed.

"Really? Are you kidding, Beckett? You think I'm going to be able to sleep after all of this?"

"Well, not right away," she scoffed, looking at her watch. "It's early yet. You have time for dinner and a couple hours of writing." She gave him a look of innocent curiosity. "You are working on the next book, aren't you?"

"Of course. Of course," he said, distracted yet again. " _Heat Rises_. It's in the early stages, outlining and such. Lots of work to do."

"Good," she nodded. "So, you do that, and we'll meet back here in the morning to find out what our victim gave her ex."

The elevator doors slid open on the ground floor just as Castle belatedly realized that she was throwing him off the scent. "Wait-" he exclaimed, but Beckett was already halfway across the lobby, headed for the parking garage.

"Night, Castle," she tossed over her shoulder, and indulged in another wicked snicker once she reached the safety of the stairwell.

* * *

A couple of hours later, Castle had fleshed out his novel outline; written half a chapter; weathered a short but vicious fight with Gina; listened obediently to Alexis's lecture about how to behave when meeting her boyfriend's parents; and spent far too long just sitting at his desk, fiddling with a pencil and brooding over the events of the day.

He'd also done a bit of desultory internet research on memory erasure technology and how to recover lost memories, but even he could see that the sites turned up by his searches were run by the absolute craziest subset of conspiracy theorists.

At last he could bear it no longer. He had to know. And he was beginning to formulate a plan.

He got up, shoved his feet into sneakers, scribbled a quick note in case Alexis woke up or Martha deigned to come home, and left.

Twenty minutes later, he was knocking on Beckett's door.

* * *

Beckett knew who it was immediately. It had to be. Who else would knock on her door this late at night?

She paused in the foyer, chewing her lower lip, wondering how to play this. Was it time to come clean, or should she string him along a little more? She didn't even know how much longer she'd be able to keep a straight face.

He knocked again, a little impatience in the timbre, and she called out "Hang on, Castle." Oops. The knocking stopped, replaced by an inquisitive silence.

"How'd you know it was me?" he asked through the door. She sighed and opened it.

"Lucky guess?" she tried. Castle huffed and strode into her apartment, his movements jerky with frustration.

"Come on in," she said sardonically. He glanced around the room.

"Josh not here?"

"No." She folded her arms defensively across her chest, unable to look at him. "He, uh, we're not, uh." Another lie she didn't want to have to reveal to Castle. She had allowed him to think things were more serious between her and Josh than they really were. No way did she need him to know that it had been little more than an extended hookup to soothe her injured feelings after watching Castle saunter away with his ex-wife at the beginning of the summer.

"Oh. Sorry to hear it," Castle said, not bothering to sound particularly sorry. Her eyes were drawn to his face, and she sucked in a small gasp. His expression wasn't anxious, curious, pleading - any of the things she had expected to see from him tonight. No, he just looked ... determined.

"I had an idea," he said, as if confirming her internal assessment of his mental state. He took a step toward her and she blinked, fighting the urge to step back.

"Oh really?" she got out, her throat tight with trepidation. With an effort, she managed to pull her composure back into place, at least enough to formulate the expected snarky response. "How unusual for you."

"Very funny," he responded, still moving toward her. "Listen, you know how sometimes you go into a room and forget what you were doing, and in order to remember it, you have to retrace your steps? Like, to jog your memory, you have to be doing what you were doing at the time."

"Uh-huh," she agreed cautiously. She wasn't sure where this was going, but there was a look in Castle's eyes that was making her decidedly nervous. "What's your point, Castle?"

"My point, Beckett," he said, taking yet another step toward her, "is that if this," a gesture toward her neck, "is really a hickey, then I should be able to reclaim my memory of how it happened by re-placing myself in the situation that caused it."

Uh-oh. Oh no. "Castle, no."

"Beckett, yes." Somehow he was inside her personal space all of a sudden, and although she hadn't intended to back away, her feet had moved of their own volition; he kept advancing, she kept retreating, until her back thumped against the wall. He was right there, far too close for comfort.

"Castle," she whispered through a suddenly dry throat. It was probably time to tell him the truth, she thought somewhat frantically, but the nearness of his body was clouding her mind, and the words wouldn't form.

"I know you think you're not supposed to tell me about it," he murmured, and there was a low husky note in his voice that she had never heard before. She liked it. Oh shit, she really liked it. "But I'll guess," he went on, "and you can just tell me if I'm ... getting warm."

Warm? He was more than warm. _She_ was more than warm, with him right there in front of her, the tantalizing smell of his cologne making her dizzy. She knew she should be objecting; she knew there were very good, urgent reasons why she should be pushing him away and telling him to stop - in fact, she was pretty sure there was something very important she was supposed to be saying right now - but her brain wouldn't cooperate.

"Oh god," was all that came out, and then Castle leaned down toward her, his hot breath flowing across the already heated skin of her neck, and she shuddered.

"So just how did you get that hickey, Beckett? Was it like this?" he asked, his voice vibrating against her sternum, and then he put his mouth on her neck, just lightly, over the hickey. No, she thought hazily, the not-hickey.

"No," she managed to say, "not-" but his lips were moving across her skin, soft and hot, and her gut clenched, the breath escaping her in a sharp exhale that almost sounded like a moan.

"How about like this?" he rumbled, and he moved his mouth slightly to the side, and swept his tongue over an unblemished part of her neck. Her whole body flushed even hotter and she gasped, her hands coming up to clutch at his shoulders. Abruptly she realized that his own hands were already on her body, resting at her waist, the heat of his broad palms radiating through her clothing. Arousal flooded through her, shocking in its intensity. But this was _Castle_! - it was a terrible idea, she knew that, even if right now she couldn't exactly remember why. Even if she wanted him so very, very much.

"Castle, no," she got out through herculean effort, and he pulled away, lifting his head from her neck to look into her face.

"No?" he questioned, studying her expression, concern tinging his features. She had to make him understand, she thought; she _had_ to, before it was too late.

"It wasn't like that," was what came out first, and she cursed herself for incoherence, then cursed herself all over again when she met his eyes and saw the heat rising there.

"What was it like, then, Kate?" he asked, low and throaty, and oh god the sound of her first name in his mouth. Her knees were weak from hearing it.

Her brain still wasn't working right, which must be the only explanation for what she blurted out next. "Castle, this memory-reclaiming experimentation thing-" what? No, she shouldn't be encouraging him! "-shouldn't you be doing this with Gina?"

Oh, that put a damper on things. He backed off further. He even removed his hands from her waist, causing another shiver to go up her spine - just from the sudden cold, she told herself firmly, nothing more.

"Gina," he said dismissively, "isn't speaking to me right now. We had a fight, and I think it might be over."

"Oh," Beckett said, "I'm sorry." Was she sorry? How terrible a person was she?

"She was pretty mad," Castle added, "especially after she saw the hickey."

Crap. This was all her fault. "Didn't you tell her it wasn't a hickey?"

"I tried," he shrugged. Beckett felt a sharp stab of guilt. If she hadn't undermined his confidence with her stupid little game...

"I'm so sorry, Castle," she said quietly. "It's my fault. I shouldn't have lied."

"Oh, it's okay, you-" He stopped short in mid-word. "Wait, lied? What did you lie about?"

Sighing, she met his eyes again. "It's not a hickey, Castle."

"It's not-" He stared at her for a long moment. "Uhh, Beckett, are you saying what I think you're saying?"

She grimaced, twisting her fingers together. "How would I know? I never know what you're thinking."

He took a fast step forward and seized her elbow, startling her. "Beckett!"

She stared up into his face, surprised. He didn't look angry, or disappointed, or any other such thing that she might expect. He almost looked ... awestruck.

"Did you seriously lie about these hickeys just to tease me?" he demanded, the beginnings of a grin twisting the corners of his mouth.

"They aren't hickeys!" she enunciated emphatically. It only made his grin spread wider across his face.

"You did. You concocted this entire scenario just to prank me because I was so excited about the whole murdered in outer space, alien invasion, government conspiracy thing. Admit it."

She gave him a sour look and a minor eyeroll. "I think I just did."

"No, come on, Beckett. Admit that this whole case is an X-File and you're loving it just as much as I am."

"That's ridiculous, Muld - I mean, Castle." Oh shit, what had she just said? She tried to turn her face away, caught between laughter and mortification, but he had hold of both her elbows now and wouldn't let her go.

"You called me Mulder. My god, Beckett, that may be the hottest thing you've ever said to me."

"Oh please," she scoffed, but he pressed her back against the wall again and she gasped. "Castle, what are you doing?"

"Didn't you always wish that Mulder would just kiss Scully already?" he asked, his face inches from hers. She swallowed thickly. Her heart was pounding, her breaths fast and shallow, staring up at him.

"Well, actually," she managed, "in season eight, episode twenty-one-"

"You are the perfect woman," Castle declared, and kissed her.

Beckett hesitated for a whole two seconds, immobile against the wall with Castle's hands back on her waist and his warm lips on hers. Then she thought, _oh, what the hell?_ and did just what she wanted to. She slid her arms around his neck and kissed him back with enthusiasm.

"I'm not dying my hair red," she gasped, when they finally broke for air. Castle chuckled softly against her cheek.

"I'll live," he murmured, and fused his mouth to hers again.

* * *

The next morning, Castle and Beckett entered the lobby of the 12th Precinct from different directions, having parted a few blocks away after one last heated kiss and surreptitious grope in her police car. Beckett drove on to the precinct parking garage and took a moment to fix her hair and lip gloss in the mirror, while Castle strolled down the sidewalk, taking a quick detour into Starbucks for their usual morning coffee.

They met up again in the lobby, greeting each other with polite _Good morning_ s, and entered the elevator, in which they stood a careful three feet apart, not speaking. Castle had attempted to negotiate on this point, with no success.

"Morning," said Ryan as they approached Beckett's desk.

"Morning."

"Morning."

"Yo," added Esposito, approaching from the break room. He cast a significant look at the turtleneck Beckett was wearing, then at Castle's button-down shirt, which was buttoned up. "How's the hickey?"

"It's not a hickey," Castle and Beckett said in unison. Ryan snickered.

"Sure, guys. Whatever you say."

"So we're back to 'not a hickey' again, eh, boss?" Espo smirked. Beckett folded her arms across her chest and glared. The smirk dropped away.

"It's from the injectors," she said, very very firmly. Both boys nodded.

"Okay."

"Gotcha."

Castle very carefully didn't look at Beckett. It was true, after all. The mark on the right side of Beckett's neck was from the injector. It was quite definitely not a hickey.

The marks on the _left_ side of her neck, however, were a different story...

* * *

 ** _Author's Note:_** _This piece of silliness was indirectly inspired by the novel Soulless by Gail Carriger, which is an excellent read; I highly recommend it. If you read it, you should have no trouble identifying the scene that prompted this story._


End file.
